NAME

sem_unlink - remove a named semaphore (REALTIME)

 SYNOPSIS

#include <semaphore.h>

int sem_unlink(const char *name);

 DESCRIPTION

The sem_unlink() function removes the semaphore named by the string name. If the semaphore named by name is currently referenced by other processes, then sem_unlink() has no effect on the state of the semaphore. If one or more processes have the semaphore open when sem_unlink() is called, destruction of the semaphore is postponed until all references to the semaphore have been destroyed by calls to sem_close(), _exit(), or exec. Calls to sem_open() to re-create or re-connect to the semaphore refer to a new semaphore after sem_unlink() is called. The sem_unlink() call does not block until all references have been destroyed; it returns immediately.

 RETURN VALUE

Upon successful completion, the function returns a value of 0. Otherwise, the semaphore is not changed and the function returns a value of -1 and sets errno to indicate the error.

 ERRORS

The sem_unlink() function will fail if:

[EACCES]

Permission is denied to unlink the named semaphore.

[ENAMETOOLONG]

The length of the name string exceeds {NAME_MAX} while {POSIX_NO_TRUNC} is in effect.

[ENOENT]

The named semaphore does not exist.

[ENOSYS]

The function sem_unlink() is not supported by this implementation.

 EXAMPLES

None.

 APPLICATION USAGE

None.

 FUTURE DIRECTIONS

None.

 SEE ALSO

semctl(), semget(), semop(), sem_close(), sem_open(), <semaphore.h>.

DERIVATION

Derived from the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995)